Primer assembly



Jan. 16, 1968 H, w c ET AL 3,363,564

PRIMER ASSEMBLY Filed Jan. 10, 1966 ill/ 51m EIG. 2 FIG. 'NVENTORS- HEINZ GAWLICK RUDOLF STAHLMANN BY ATT NEYS.,

United States Patent Ofi ice 3,363,564 Patented Jan. 16, 1968 3,363,564 PRIMER ASSEMBLY Heinz Gawlick and Rudolf Stahlmann, Furth, Bavaria,

Germany, assignors to Dynamit Nobel Aktiengesellsehaft, Troisdorf, Germany Filed Jan. 10, 1966, Ser. No. 519,557 Claims priority, application Germany, Jan. 15, 1965, D 46,249 19 Claims. (Cl. 102-45) ABSTRACT OF THE DESCLOSURE The present disclosure relates to a fuse or primer assembly and more particularly, to a manner of securing a primer element on a primer support, especially in the bottom of cartridges for mortar and artillery ammunition. A cup-shaped cap with an outer annular flange overlies the primer and an annular deformation of the support engages the flange outwardly of the primer rim, which is clamped between the bottom of the cup shaped portion of the cap and the support.

It is known in the prior art in connection with mortar and artillery ammunition to utilize as primer or fuse element a screw-threaded screw member with a pressed-inprimer composition which is threaded from the outside into a corresponding threaded bore of the cartridge bottom. Also known in the prior art is a threaded nipple with a pressed-in primer composition which is threaded from the inside into a dead-end bore provided with a thread of the cartridge bottom. Both types of primer or fuse elements are relatively complicated and costly as regards the manufacture of the parts thereof. It is considerably more simple and less costly to manufacture another type of fuse or primer element, in which the primer composition is accommodated in a casing closed on one side by means of a bottom having a laterall projecting rim. With this type of primer element, one encounters however, considerable difficulties to achieve a securing on the primer support or in the cartridge bottom which is completely satisfactory from a moisture-tightness point of view and completely satisfactory against inadvertent falling out. Though it is possible to secure the casing, which is inserted with its stem more or less firmly in a corresponding aperture of the primer support or cartridge bottom by annular riveting or peening over of the cartridge bottom in such a manner as to be sufiiciently secured therein against inadvertent falling out, this measure is very questionable in view of the great sensitivity of such primer elements which is the reason why it is utilized reluctantly, the more so as the bottom of the casing has to be protected also as much as possible against excessively strong impacts in order that the same is not perforated during the firing.

' The present invention is concerned with primer or fuse elements of the last-mentioned type and aims, under elimination of the aforementioned disadvantages, at a simple solution for the securing thereof on the primer carrier or support, which not only assures a moisture-tight closure and sufiicient safety against falling out but also enables by means of simple mechanical measures to utilize one and the same primer element in the same, unchanged construction with different primer carriers or supports and to match the same also to differing sensitivity requirements. It is proposed in connection therewith according to the present invention to insert the case, with the front end surface of its projecting rim abutting at the trimer support, into a corresponding aperture formed in the primer support and provided with an adjoining ignition channel and to cover the case by means of a cap having a flange-like rim which abuts flush against the bottom surface of the case and overlaps the projecting rim of the case with lateral play, whereby the cap is retained on the primer support by means of an annular lip formed on the primer support and flanged over the rim of the cap by cold deformation, for example, by means of a forming die or annular riveting.

Accordingly, it is an object of the present invention to provide a primer assembly for mortar and artillery ammunition of the type described above which eliminates, by extremely simple means, the aforementioned shortcomings and drawbacks encountered with the prior art constructions.

It is another object of the present invention to provide a primer assembly for mortar and artillery ammunition which is relatively inexpensive in manufacture, requires relatively few parts and can be readily installed without expensive and complicated assembling techniques.

A further object of the present invention resides in a primer assembly which is not only relatively inexpensive and simple but which also assures a completely satisfactory moisture tightness coupled with completely satis factory safety against any possible falling out of the primer or fuse element.

Still another object of the present invention resides in a primer assembly of the type described above which realizes the aforementioned aims and objects without exposing the primer element to the danger of unintentional ignition owing to its high sensitivity.

These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, one embodiment in accordance with the present invention, and wherein:

FIGURE 1 is a partial crosssectional view through one embodiment of a primer assembly in accordance with the present invention; FIGURES 2 and 3 show modified details of FIGURE 1 with like numerals for corresponding elements.

Referring now to the drawing, reference numeral 1 designates therein the primer support or carrier of any conventional construction which is provided with an aperture 2 and an adjoining ignition channel 3. The primer element consisting of the case 4 and of the primer composition arranged therein (not shown in the drawing) is inserted into the aperture 2 of the primer support 1. The primer element 4 abuts with the forward end surface 6 of the laterally projecting rim 5 thereof against the end surface 7 of the ring-shaped enlargement 8 of the aperture 2. The cap 10 abuts flush against the bottom surface 9 of the case 4 and overlaps the rim 5 of the case 4 with lateral play. The cap 10 is retained on the primer support 1 with its flange-like rim 11 by means of the inwardly flanged-over annular lip 12.

As can be readily seen from the drawing, the conditions and relationships are chosen exactly in such a man ner that the outer surface 13 of the cap 10 terminates eX- actly flush with the surface 14 of the primer support 1. This is achieved in that the height or depth of the enlargement 8 is selected equal to the height of the rim 5 plus the wall thickness of the cap 10. At most the height of the cap 10 can be made equal to the height of the recess 8 if a flush termination of the cap 10 with the primer support 1 is to be assured. In order to assure in every case a flush abutment of the cap 10 against the bottom surface 9 of the case 4, the height or depth of the recess 16 of the cap 10 can, of course, under no circumstances be larger than the height of the rim 5 whereby always the minimum height of the rim 5, determined within the range of the permissive manufacturing tolerances has to be used as basis for such consideration.

The cap 10 is arranged in the illustrated embodiment with some radial play in the enlargement 8; of course, the dimensions can also be so chosen fitting accurately. At least with the illustrated embodiment this is not necessary, as in this case the annular lip 12, whose initial configuration prior to its deformation is indicated only schematically and obviously only for exemplary purposes by the dash line, prevents with certainty a radial displacement of the cap 10. However, also in the case when the annular lip 12 should extend only over a smaller portion of the flange rim ll of the cap 10, any undesired lateral displacement of the cap 10 can be avoided if care is taken that the cap 10 is pressed sufficiently strongly against the bottom surface 9 of the case 4.

A construction of the primer support 1 in such a mannor that the initial configuration of the annular lip 12 iilustrated in dash lines represents a ring of wedge-shaped cross section extending between the enlargement 8 and the ring-shaped recess 17, is obviously to be taken only for illustrative purposes. Other shapes and dimensions of the original cross section of the annular lip 12 are, of course, within the frame of the present invention and readily within the scope of a person skilled in the art. It is essentially above all that for the end shape of the annular lip 12 intended to be achieved in a given case a corresponding material cross section is available which can be readily calculated.

Furthermore, a recessed arrangement of the illustrated type is, of course, not necessary in every case though it appears appropriate and is also recommended if the securing of the primer element is realized approximately directly in the bottom of a cartridge. However, if the assembly relates to the securing of the fuse or primer element in a fuse or primer screw member which, in its turn, can be threaded to a greater or lesser extent intO the bottom of the cartridge by means of a thread, it is quite feasible and suflicient if the cap It the annular lip 12 and possibly also the rim project to a more or less large extent or also completely over the primer support 1 whose surface 14 may then extend corresponding to the dash and dot line indicated in the drawing.

As may be further readily seen from the drawing, the ignition sensitivity of the primer element is determined essentially by the thickness of the cap 10. Accordingly, one is in a position to vary the ignition sensitivity within wide limits and independently of the primer element by changing the thickness of the cap and possibly by a corresponding matching of the individual parts of th arrangement and to thus adapt the ignition sensitivity to the given application purpose.

Furthermore, it should be noted that the illustrated axial extent of the aperture 2 as well as the arrangement and construction of the ignition channel 3, which may additionally be filled with a booster charge, are to be construed only in an illustrative sense and can also be selected differently. It is only essential that the axial extent of the aperture 2 is so great that the forward end of the case 4 does not abut against the primer support 1 as otherwise a flush abutment of the forward end surface 6 of the rim 5 against the end surface 7 of the enlargement can no longer be assured safely.

To assure a completely moisture-tight closure, it is also of advantage if, prior to the flanging or bending of the annular lip 12, a sealing lacquer or the like of any known type is applied to the rear end surface 15 of the rim 11.

While we have shown and described one embodiment in accordance with the present invention, it is understood that the same is not limited to the details shown and described herein, but is susceptible of numerous changes as known to a person skilled in the art, and We therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

We claim:

1. A securing arrangement of a primer element on a primer support, especially in the bottom of cartridges for mortar and artillery ammunition, comprising: a primer having an axis, a forward axial end and a rearward axial end; said primer having a main forward body portion and a rearward annular rim extending transversely outwardly from said main body portion with respect to the axis to define a rim forwardly facing substantially annular support shoulder and a rearwardly facing surface; a relatively rigid primer support having a rearwardly open axially extending main aperture receiving therein said primer body; said primer support having a relatively rigid rearwardly facing substantially annular support surface substantially annularly engaging said rim forwardly facing substantially annular support shoulder; a cap having a central portion defining a forwardly facing surface engaging said primer rearwardly facing surface; said cap having a flange transversely extending outwardy from said central portion and outwardly with respect to said primer rim to define a rearwardly facing surface; said primer support having a portion outwardly and rearwardly overlapping said cap flange, and engaging said cap flange substantially only transversely outwardly of said primer rim and on said cap flange rearwardly facing surface.

2. The device of claim 1, wherein said primer support has an annular enlargement aperture enlarged with respect to and rearwardly of said main aperture receiving therein said rimer rim and defining said primer support rearwardly facing substantially annular support surface; said cap central portion is cup-shaped with a generally forwardly extending annular side wall axially overlapping said primer rim; said cap flange is annular and extends outwardly from the forward end of said cap side wall; said primer support portion is an annular lip rearwardly extending to outwardly axially overlap said cap flange and is annular inwardly deformed to rearwardly overlap said cap flange.

3. The device of claim 2, wherein said cap has a rearmost transverse surface substantially flush with the rearmost transverse surface of said primer support.

4. The device of claim 3, wherein said primer support has an annular recess outwardly of said annular lip.

5. The device of claim 4, wherein said primer main forward body is cylindrical; said rim forwardly facing substantially annular support shoulder extends in a plane substantially perpendicular to the axis; said primer rearwardly facing surface extends in a plane substantially perpendicular to the axis; said primer support rearwardly facing substantially annular support surface extends in a plane substantially perpendicular to the axis; said cap forwardly facing surface extends in a plane substantially perpendicular to the axis; said cap flange extends in a plane substantially perpendicular to the axis; said cap annular side wall extending generally axially.

6. The device of claim 2, wherein said primer main forward body is cylindrical; said rim forwardly facing substantially annular support shoulder extends in a plane substantially perpendicular to the axis; said primer rearwardly facing surface extends in a plane substantially perpendicular to the axis; said primer support rearwardly facing substantially annular support surface extends in a plane substantially perpendicular to the axis; said cap forwardly facing surface extends in a plane substantially perpendicular to the axis; said cap flange extends in a plane substantially perpendicular to the axis; said cap annular side wall extending generally axially.

7. The device of claim 3, wherein said primer main forward body is cylindrical; said rim forwardly facing substantially annular support shoulder extends in a plane substantially perpendicular to the axis; said primer rearwardly facing surface extends in a plane substantially perpendicular to the axis; said primer support rearwardly facing substantially annular support surface extends in a plane substantially perpendicular to the axis; said cap forwardly facing surface extends in a plane substantially perpendicular to the axis; said cap flange extends in a plane substantially perpendicular to the axis; said cap annular side wall extending generally axially.

8. The device of claim 1, wherein said cap has a rearmost transverse surface substantially flush with the rearmost transverse surface of said primer support.

9. The device of claim 2, wherein said annular lip forms a homogeneous integral part of said primer support.

10. The device of claim 1, wherein said primer body portion is of an axial extent at most slightly less than the axial depth of said main aperture.

11. The device of claim 1, wherein said cap overlaps said primer rim with transverse play.

12. The device of claim 1, wherein said cap flange has a forwardly facing annular surface tightly engaging said primer support rearwardly facing substantially annular support surface.

13. The device of claim 1, wherein said cap flange is annular, said primer support portion is annular and annularly engages said cap flange over its entire rearwardly facing surface.

14. The device of claim 1, wherein said cap flange is annular, said support surface portion is annular and engages said cap flange only over a portion of its rearwa-rdly facing surf-ace, and said cap central portion firmly engages said primer to prevent transverse displacement of said primer.

15. The device of claim 2, wherein said primer support enlargement aperture has an axial depth substantially equal to the axial depth of said primer rim and said cap central portion.

16. The device of claim 15, wherein the total axial height of said cap is at most equal to the axial depth of said primer support enlargement aperture.

17. The device of claim 15, wherein said cap cupshaped central portion has an inside axial dimension at most equal to the axial height of said primer rim.

18. The device of claim 2, wherein the total axial height of said cap is at most equal to the axial dimension of said primer support enlargement aperture.

19. The device of claim 1, wherein said cap central portion is substantially cup-shaped with an inside axial depth at most equal to the axial dimension of said primer rim.

References Cited UNITED STATES PATENTS 855,958 6/1907 Loeble 102'-45 932,562 8/ -9 Muenzenmaier 10245 2,522,208 9/1950 Catlin 10'2-45 

